I'm going CRAZY because i'm uploading any CSS files (style.css from main theme, css from plugins, css from every single thing) over and over and they are old versions which don't refresh to changes (this have been happening some days ago, not sure when maybe 1 week ago or so, and i ended up realizing yesterday because i was focused editing other php files)but PHP files are updating instantly and without having to clear any kind of caché.

I've read so many questions/answers tutorials relative to this matter and is impossible for me to do it.

1.I'm 99% sure is not a matter of Caché. I have W3TotalCache and disabled it uninstalled and the issue stills there, i deleted/destroyed every single piece of cache in my browser, flush dns my connection, everything i try to access from other computers and happens the same.

2.I deactivated every single plugin i even deleted all the folders of plugins and restored them and happens the same.

3. I restored 1 by 1 every single file CSS & PHP file i modified from the original template, and happens the same.

4. I restored my .htaccess various times, happens the same.

5. Can it be a matter of FTP permissions?

6. Can it be my host? 1and1 is giving 503 errors and stuff this last week every single time someone logins, could it be related?.

The CSS that is appearing in the browser lacks of css styles that appear in the main file i'm uploading, and the incredible thing is that in wordpress editor of style.css (and other css files) show the new lines i did but they do not appear when navigating on the website.

To give you an example, i've modified the position of the header from relative to absolute, and still giving relative no matter what i do. Also appears like 10 lines above of what it really is. I restored the original style.css and happens the same, is like no matter what i end up uploading that stuff is frozen for eternity.

I'm glad the changes are working using this plugin BUT for me is very uncomfortable having to use this plugin instead of modifying the root css files, because is easy to add css rules, but if i want to modify or delete something?

After 14h of nonstop working i found the problem. Was pathetic. I had enabled the
?ver=1.0 on CSS that's why those files weren't caching and i used the functionality of hide_my_wp plugin to disable them. Now all CSS is getting updated as usually. I seriously went insane for a whole day. Finally i made it, thank you for everything.

What do you mean by that? I'm having the same issue and scratching my head. I made changes in the editor and they're there, but not showing up on my site. I've purged the cache and cleared all my browser history. Frustrating!